Various headlamp cleaning systems are known wherein a headlamp with a housing; a source of light and a covering lens is cleaned by a lens washer system including a source of fluid, a pump for the fluid and a nozzle for distributing the fluid against the lens for removing dirt build-up.
One such system is set-forth in U.S. Pat. Nos. 3,609,450 and 3,736,560. These patents disclose a controller that senses dirt build-up on a lens by use of a photometrics sensor that is separate from the headlamp. The controller includes a dash board display of headlamp condition after washing.
U.S. Pat. No. 4,713,583 discloses a cleaning system wherein the headlamp dirt build-up sensing is provided by reflective sensing and the sensor is integrated within the headlamp.
U.S. Pat. No. 4,210,841 discloses a headlamp assembly having a plastic lens but there is no suggestion of a dirt build-up deterioration of the lens affecting the transmission of light.
While suitable for their intended purpose, the aforesaid prior art arrangements do not disclose the use of headlamp cleaning systems especially adapted for use with light sources such as an HID (high intensity discharge) headlamp or a tungsten halogen headlamp that includes a plastic lens. In such cases the road dirt on the surface of a plastic lens covering a high temperature, high intensity discharge lamp such as is the case with HID headlamps can be literally baked onto a lens so that the outer surface of the lens becomes less light transmissive over time even after a washer cleaning cycle or cycles.